Liquid storage reservoir



May 15, .1933' J. A. BJERREGAARD 1,909,484

LIQUID STORAGE RESERVOIR Filed April 14. 1931 2 Sheets-Sheet 1 IIIIIIllll Illll llllll 1,23 1 A, ATTORNEY May 16, 1933. J. A. BJERREGAARDl1,909,484

LIQUID STORAGE RESERVOIR INVENTOR JAM E6 A. Bd ERREGAARD ATTORNEYPatented May 16, 1933 Umso STATES JAMES A. BJERREGAARD, OF FOREST HILLS,NEW YORK, ASSIGNOB T" DOHERTY RESEARCH COMPANY, OF NEW YORK, N. Y., AOORPORATlON 0F DELAWARE LIQUID STORAGE" RESERVOIR Application led April14,

This invention relates to liquid storage reservoirs and moreparticularly to a novel design of large capacity oil storage reservoirsof the earth embankment type and a iioating roof therefor.

1n designing andbuilding large capacity oil storage reservoirsheretofore it has not been found practicable to combine the quali" tiesof stability, durability, comparatively inexpensive construction andhigh eiiiciency in preventing oil loss by seepage and evaporation.Various types of large capacity reservoirs have been suggested asembodying one or more of these qualities but in each of such suggestedreservoirs at least one of the above qualities so essential to efcientoil storage is lacking. Particularly in reservoirs of the earth fill orearth embankment type it has been found impossible heretofore to combinein both the reservoir design and in the roof design a comparativelyineX- pensive construction, and stability, with high eticiency in theprevention of oil losses due to leakage and evaporation,

@ne object of the present invention is to provide a large. capacityliquid storage reservoir of the earth embankment type which is stable,durable, comparatively inexpensive to build and is highly etiicient inpreventing losses by leakage and evaporation.

Another object of the present invention is to provide a iioating rooffor such a large capacity liquid storage reservoir of the earthembankment type which will be of simple and inexpensive construction andof high efliciency in preventing evaporation losses under all weatherconditions.

Other objects and advantages of the in vention will be apparent Jfromthe following detailed description, taken with the ac companyingdrawings, in which:

Fig. 1 is a partly diagrammatic top plan view of an oil storagereservoir and root embodying the preferred design of the presentinvention.

Fig. 2 is an enlarged plan view of one portion of the reservoir roofshown in Fig. 1, parts being broken away to show the con struction otunderlying parts.

L Fig.v 3 is a view in vertical crossesection 1931. Serial No. 529,936.

ot a part oi' the reservoir according to the present invention, showingthe relation of the floating roof to the walls and -floor of thereservoir.

Figs. 4,y 5, 6, and 7 ,show various forms of joints which may be used toadvantage in the construction of .the reservoir roof.

Referring to the drawings, 10 indicates the earthen Wall of the earthembankment type reservoir according to the present invention. This wallmay be circular or oval in shape and may be oi' any suitable dimensionsso as to provide a reservoir of the desired capacity. The wall is bankedon both sides to such a degree that it is stable under full capacitypressure. The inside surface of the wall embankment 10 is constructed ina series of steps 12 extending inwardly from the top. to the floor 14 ofthe reservoir, and each step is retained by a vertical ring 16 oit'corrugated metal or concrete which extends a short distance abovethesurface of each step. The top surface of each step 12 and oi' thereservoir floor 14 is treated with asphaltum so as to make the surfacesimpervious to Water. In this Way the tendency of the wall embankment orthe loor of the reservoir to absorb the water, such absorption tendingtoward a subsequent instability of the wall embankment, is obviated, andby reason of the retaining rings 16 a body of water 18 is constantlymaintained on each of the steps 12 ot the embankment.` Similarly, a bodyof water 19 is constantly maintained on the floor 14 of the reservoir byreason of a water outlet pipe 2O having an outlet opening which isslightly above the floor level of the reservoir; Liquid t'orkthe waterbodies 18 and 19 is introduced through an inlet pipe 21 located abovethe top step of the reservoir wall which maintains a body of water. Thereservoir is also provided with an oil inlet and outlet pipe 22. Y

Referring now more particularly to the roof 23, 24'indicates the curvedpans of the peripheral portion 25 of the roof which are joinedtogetherat 26 and 28 in a manner which will hereinafter be more fully described.f The pans 24 are of inverted semicylindrical cross section constructedof ilexible sheet metal and are joined together both endwise andsidewise to torni a series ot connected annular rings 27, the ringsbeing concentrically arranged and overlying the steps l2 of the insidesurface ot' the wall embankment.

The central portion of the roof 29 is composed of rectilinear rows oi'straight pans 30 of inverted semi-cylindrical cross section constructedof flexible metal and joined together at 32 and 34. The joints 32 and 34are formed in a manner which will be hereinafter more fully explained.rlhe central portion of the roof 29 overlies the vhoor 14 of thereservoir.

The central series of pans 30 are joined to the peripheral series ofpans 24 at 36 in any suitable manner such as by welding or bolting. Theouter series of pans 24 of the peripheral portion of the rooi are joinedto the walls of the reservoir by means of a metal ring strap 38. Thisstrap 38 is welded or bolted or fastened in any other suitable way to aring 40 which retains one ot the upper steps ot the wall embankment sothat the joint thus made will be practically air-tight and liquid-tight.

Above the peripheral portion 25 of the root is placed a series ofannular pontoon members 42 constructed of metal tubing and attached tothe annular rows ot pans 24 at the joints 28 between the vario-us rowsby means of guys44. Similarly above the central portion 29 of the rootis a series of rectilinear pontoon members 46 constructed of metaltubing and attached to the rectilinear rows of pans 3() at the joints 34between the various rectilinear rows by means of guys 48. The purpose ofthese pontoon members will be more 'fully hereinafter discussed. Abovethe roof and to one side of the reservoir is a water inlet pipe 50 forproviding a water seal tor the reservoir.

Figs. 4 and 6 show forms oi joints which may be used at 26 and 32, Fig.4 showing a bolted joint having a gasket 52 and bolting bars 54, andFig. 6 showing` a pressed joint. Figs. 5 and 7, show forms of jointswhich may be used at 28 and 34,V Fig. 5 showing a bolted joint having agasket 56 and boltinfg bars 58, and Fig. 7 showing a rolled joint. Whileany suitable type of joint may be used in the construction of the rootof the reservoir according to the present invention, the types abovedescribed are preferable in that they can be made practically air-tightand liquid-tight, and their simple design facilitates quick 'and easyassembly of the roof.

When the: reservoir is full, the roof will take the position shown at60, since by reason of the air-tight and liquid-tight connectionsbetween the various sections of the root it will float on the surface ofthe oil in the reservoir. By allowing the water to flow from the waterinlet 50 onto the roof a water seal is formed and maintained above theroof, the roof then acting as a ilexible membrane between the oil andthe water. A slight flow of water is constantly maintained from theinlet pipe 2l on to the steps l2 and progressively downwardly Jfrom stepto step until it inally reaches the floor of the reservoir. The waterlevel on the floor 14 may be maintained constant by allowing thesuperuous water to escape over the weir at the top of the pipe 20. Thusa constant level of water may be maintained on the roof, the steps, andthe floor of the reservoir, which bodies of water act as a completewater seal for the body of oil in the reservoir.

When the oil is withdrawn from the res ervoir through the pipe 22 theoil level will drop and the roof will drop accordingly to a positionshown at 62. As the rootl lowers, the flexibility of the metallic panand pan joint construction allows the pan rows to diametrically expandand iiex so that the peripheral joints 23 between the outer annular rowsof pans will rest upon each successively lower step l2, the jointsbetween pan rows being water-sealed by the body of water which ismaintained at each step, and by that portion oi the water above the roofas shown at 64 which normally remains between the series ot pans as theroof lowers, thus giving an increasingly tighter water seal to the oilwithin the reservoir. The pontoon members 42 will lower with the surfaceof the water constituting the water seal above the rooie until they restupon and between the outer rows ot' pans 24.

lWhen the oil is substantially all withdrawn from the reservoir, theroot will lower to the position shown at 66 so that the central portionot' the rooic will rest upon the iioor of the reservoir. When desiredthe reservoir may be again iilled by flowing the oil into the reservoirthrough the pipe 22, and the rootI will be raised accordingly.

lnasmuch as the roof acts only as a flexible membrane between the oil inthe reservoir and the water seal above the roof, it is subject to anydilierential in pressure between the oil and the water at any point onthe surface of the oil. lized in some way as by means of the pontoonmember 42 and 46. lt the water above the root is displaced by any of anumber o'l causes such as the application of a local load Accordinglythe roof must be stabi- EGO or the action of the wind on the free waterfifi.

any tendency of the roof membrane to lift is resisted by the overlyingwater when the buoyancy of the pontoon members is reduced. rllhe roofistherefore constantly in a state of stable equilibrium.

lt may be seen from the above detailed description that the reservoirand roof design of the present invention is of high durability, is ofgreat stability, is of comparatively inexpensive and simple constructionand is of high efficiency in preventing oil loss by seepage andevaporation. The reservoir and roof have particularly high efficiency inpreventing oil loss by evaporation or leakage, since the body of oil iscompletely enclosed by water seals.

An additional advantage of the roof design is that the units of the roofmay be shop fabricated, shipped nested, and erected in the field. Thebolted joints between the pan units are also of particular advantagehere in that they facilitate erection of the roof and allow replacementof pan units without emptying the reservoir. Easy replacement may beeffected by removing the water seal and blowing the air into the pans inthe rows adjacent the row in which the pan is to be replaced,

thus raising that portion of the roof sufhciently to allow thereplacement.

What is claimed as new is:

l. An oil storage reservoir having upwardly diverging inner side wallsformed as a series of steps and means for retaining individual steps andfor maintaining bodies of liquid on each step.

2. An oil storage reservoir having a floor and 'upwardly diverging sidewalls with a stepped inner surface, the surface of said floor and saidsteps being treated to be impervious to water, means for retainingindividual steps and for maintaining a body of water on each step andmeans for maintaining a body of water on said floor.

3. An oil storage reservoir having side walls with a sloping innersurface and a flexible roof of a cross-sectional areal sufficient tocover the surface of the oil when the reservoir is full and to extend tothe upper periphery of the reservoir wall to which it is fastened, saidroof consisting of a plurality of flexible metal segments connected endto end and side by side in rows by air-tight and liquid-tightjoints soas to float on the surface of the oil within the reservoir and by itsflexibility to conform to the shape of the wall and to rest thereon asthe level of the oil in the reservoir is lowered.

4l. An oil storage reservoir having inner side walls formed as a seriesof steps and a roof of sufficient cross-sectional area. to cover thesurface of the oil when the reservoir is full and to extend to the upperperiphery of the reservoir wall to which it is fastened, said roofconsisting of a plurality of inverted flexible metal pans ofsemi-cylindrical cross section connected end to end and side by side inrows by air-tight and liquid-tight joints so as to float upon thesurface of the oil and the peripheral portion of said roofconsisting of4 pan rows that overlie and conform to the shape of the steps of theside walls so that the joints between said pan rows will rest uponsuccessively lower steps of the wall as the level of the oil in thereservoir is lowered.

5. An oil storage reservoir roof consisting of a plurality of invertedflexible metal pans of semi-cylindrical cross section connect-ed end toend and side by side in rows by airtight and liquid-tight joints, saidroof being adapted to float upon the surface of the oil within thereservoir and to conform' in contour with upwardly diverging reservoirwalls.

6. An oil storage reservoir roof comprising a plurality of flexiblemetal segments of two different patterns the segments of one patternhavingcurved edges to conform to the shape of the reservoir wall and thesegments of the other pattern having straight edges, said segments beingconnected end to end and side by side in rows by air-tight andliquid-tight joints to form a peripheral roof section of annularconcentric segment rows and a central roof section of rectilinearparaliel segment rows.

7. An oil storage reservoir roof having a peripheral portion and acentral portion, the said peripheral portion consisting of a pluralityof flexible metal pans of inverted semi- Y cylindrical cross sectionconnected end to end and side by side in rows by air-tight andliquid-tight oints shaped to conform to the contour of the reservoir andto form an annular concentric series of pan rings, and the said centralportion consisting of a plurality of flexible metal pans of invertedsemi-cylindrical cross section connected end to end and side by side inrows by air-tight and liquidtight joints to form a parallel rectilinearseries of pan rows, the said peripheral portion having air-tight andliquid-tight connections with the said central portion.

8. An oil storage reservoir comprising sloping side-walls and a roof,said roof consisting of avperipheral portion and a central portion offlexible metal pans of inverted semi-Cylindrical cross section,connected end to end and side by side in rows by air-tight fies andliquid-tight joints, the said peripheral4 portion forming an annularconcentric sea floor and side walls with a stepped innerv4 13@ surface,said roof consisting of a peripheral portion and a central portion of aplurality of flexible metal pans of inverted semi-cylindricalcross-section connected end to end and side by side in rows by air-tightand liquidtight joints so as to form a series of pan rows which floatupon the surface of a body of oil within the reservoir, the pan rows ofsaid peripheral portion overlying and conforming to the shape of thesteps of the side walls and having a width substantially the same as thewidth of said steps so that the joints between said pan rows will restupon successively lower steps of the wall as the level of the oil in thereservoir is lowered and the pan rows of the said central portionoverlying` the floor of the reservoir so as to rest thereon when-the oilsupply within the reservoir is sufficiently depleted.

l0. An oil storage reservoir, having sloping side walls and a roof, saidroof consisting of a plurality 'of inverted ieXible metal pans ofsemi-cyindrical cross section connected end to end and side by side inrows and to the upper periphery of the said side walls by airtight andliquid-tight joints, a water seal upon said roof and a series of pontoonmembers attached to and above said roof.

ll. An oil storage reservoir having side walls and a roof, said roofconsisting of a peripheral series of concentric rows of flexible metalpans of inverted semi-cylindrical cross section connected end to end andside by side by air-tight and liquid-tight joints and a central seriesof rectilinear rows of flexible metal pans of inverted semi-cylindricalcross section, connected end to end and side by side by air-tight andliquid-tight joints7 a water seal above said roof, an annular concentricseries of pontoon members attached to and above the peripheral portionof' said roof and a parallel rectilinear series of pontoon membersattached to and above the central portion of said roof.

12. An oil storage reservoir having a floor, side walls with a steppedinner surface, a roof consisting of a plurality of flexiblemetalsegments connected end to end and side by side in rows by air-tightand liquid-tight joints and connected to the upper periphery of the wallof said reservoir, means for retaining said steps and for maintaining` awater seal thereon, means for maintaining a water seal on said floor andmeans for maintaining a water seal above said roof.

13. An oil storage reservoir roof having a plurality of flexiblesegments connected end to end and side by side in rows by air-tight andliquid-tight joints, said roof being adapted `to float upon the surfaceof the oil within the reservoir and to conform in contour with thereservoir walls, a water seal above said roof and a series of pontoonmembers attached to and above said roof for keeping said JAMES A.BJERREGAARD.

